package src.CodeTopSecondPractice;

public class _21 {
    public ListNode mergeTwoLists(ListNode l1, ListNode l2) {
        if (l1 == null && l2 == null)
            return null;
        if (l1 == null)
            return l2;
        if (l2 == null)
            return l1;
        ListNode newNode = new ListNode(0);
        ListNode cur = newNode;
        while (l1 != null && l2 != null) {
            if (l1.val >= l2.val) {
                cur.next = l2;
                l2 = l2.next;
            }else {
                cur.next = l1;
                l1 = l1.next;
            }
            cur = cur.next;
        }
        if (l1 != null) {
            cur.next = l1;
        }else if (l2 != null){
            cur.next = l2;
        }
        return newNode.next;
    }
}
